From Behind the Grate
by DrunkRooster
Summary: Nepeta is drawn to the noises that she hears in the ventilation shafts at night, and decides to check it out. Smut.


From Behind the Grate

Nepeta always knew when Karkat was in Terezi's room. She could always hear Terezi through the ventilation system, usually waking Nepeta up from her cat naps.

She remembers the first time she hear her moans echoing through the vents. Nepeta crawled silently towards Terezi's room through the shafts. Perhaps she would get more data for her shipping wall, she though to herself. As she gazed through the grating, she saw that it was Karkat standing there, pumping away at Terezi as she laid on her back.

"F4ST3R," she cried out pounded away between her legs, each thrust creating a sloppy wet sound. He grabbed her bare breast as she rolled her head and Karkat let out a loud grunt and a final thrust. After a moment of panting, he pulled out, their teal and red genetic material dribbling from her legs.

Slowly, Nepeta crept away to her little hovel where she slept, a bitter sadness in her chest as she wiped away a welling tear from her eye. From that day onward, Karkat and Terezi would have sex almost every day and every time they did Nepeta would hear them. It would leave her upset, and she tried her best not to listen to them, but at the same time, she was strangely curious as well.

At times, she would crawl through the vent to the grating to watch them. Terezi didn't have the largest breasts of her friends, but they were bigger than hers. They were also the perfect size for Karkat to cup in his has, and her voice would shriek with pleasure when Karkat put them in his mouth, kissing them and ever so slightly nibbling them with his nubby teeth.

There was one time when Nepeta was spying on them she saw Karkat tied to the bed, blindfolded. Terezi was in a version of her FLARP costume Nepeta never knew she had. It had a crotchless section, which showed off her wet teal pussy. The red jacket hung open on her, and the teal top that was supposed to be under it was crumpled in the corner.

"1 TH1NK 1 KNOW HOW TO S3T YOU STR41GHT," Terezi licked her lips as she slowly stroked Karkat's shaft. She gave it a lick, starting from the base to the tip with her long black tongue, as if to savor the taste. Reaching the tip, she would play with the entrance of his dick, licking the pre-cum off, before opening her mouth and starting to suck. Her head would bob up and down, go down further and further and before long, Terezi was practically swallowing his penis.

"I'M CUMMING," Karkat shouted, as he released his candy red cum on to Terezi's face and hands.

Terezi licked some of the cum off her fingers. "1 LOV3 TH3 T4ST3 OF YOUR CH3RRY," she giggled as she moved on top of him, rubbing his penis with her glistening slit. "H3 H3 H3, I KNOW YOUR NOT DON3 Y3T!" She guided him inside her, slowly lowering her hips till she reached the base. Her hips started to move back and forth slowly, then she started to mover faster. And faster. And faster, and soon, they were both moaning together. Terezi's hips were moving like a piston, and the sound of their flesh hitting each other got louder and faster every time till both of them released inside each other, with their voices so loud, Nepeta could hardly believe that no one else could hear it.

Nepeta never mentioned to Karkat that she knew about his sexual relationship with Terezi. No one else seemed to know about it though, or at least, no one ever talked about it. Perhaps the big metal doors blocked out all the sound, the only place to hear it being from the vents which Nepeta frequent.

Soon enough, Nepeta started to get aroused when she hear them fucking. She would crawl to her spot behind the grate and watch them, and before long she would start caressing her body, tracing the outline of her small breasts through her shirt and touching her seed flap through her pants. She would close her eyes, and imagine Karkat standing over her, thrusting inside her, saying her name instead of Terezi's.

She stopped herself the first couple of times she realized what she was doing. She shouldn't even be there. If she went any further, they would notice and she wouldn't be able to handle the shame of Karkat catching her. Despite this, her hands would always wander. She would find her hands creeping under her shirt to her tiny breasts and down her pants, till she realized what she was doing and stopped herself.

One night, she was once again drawn to the grate. Terezi was bent over her desk, Karkat taking her from behind. From the angle of the vent, Terezi's face was completely hidden from view, but Nepeta could see Karkat, gritting his teeth, grunting like a beast. He would slap her ass with a loud thwack, leaving behind a teal shaped handprint.

Nepeta found her hands wandering again as she watched them, picturing herself in that position. She let her hand slip into her panties, over her coarse pubic hair to her slit. It was starting to get wet as she inserted one of her fingers slowly, moving her hips slightly, imagining Karkat's dick was sliding into her, moving with the same savage speed and force as he was with Terezi. It felt so good.

She rolled over onto her back and unzipped her pants. She slipped in another finger, moving her hips in rhythm, closing her eyes.

":33 K-kar-kitty" She whimpered as she quickened her pace. She lifted her shirt, reveling her tiny breasts to the cold air of the vent and grabbed one of them hard, digging her nails into it. The sound of her fingering sliding in and out of her wet thighs echoed through the vents, and a for a moment, Nepeta thought Karkat and Terezi heard her. She peeked through the grate, where Karkat was panting furiously.

There was a slight pause, and Karkat pulled out from Terezi. Nepeta eyes widened as she thought she had been discovered, and yet she couldn't stop moving her hands, the wet sound filling her ears. Her eyes were fixated on Karkat's pulsing cock, and she wondered how it would feel around her lips, moving in her tiny pussy.

Karkat flipped Terezi over, so she was facing him now, and Terezi let out a gasp as Karkat stuck his cock in her again. As he continued his furious fucking, Karkat leaned in and kissed Terezi. Their lips locked, tongues swimming over each other in their mouths. Nepeta closed her eyes once again, and moved her tongue around in her own mouth. The thought of Karkat kissing her during sex made her hands and hips move all the more faster. She tried to stifle her cries, making quiet whimpering noises. The hand groping her breast moved to her clitoris, rubbing it at the same time as her fingers quickly moved in and out.

Karkat broke away from Terezi's lips, saliva trailing from his mouth. "I'M GOING TO CUM,"

":33 cum inside me, cum inside me," Nepeta begged quietly. She was going to cum. Her legs trembled and her back arched as she squirted her genetic material all over the inside of the ventilation shaft. She laid in the shaft, exhausted. Her body was warm, but she could feel the cool air of the vents blowing on her bare pussy and exposed breasts. The breeze felt nice on her, and she rolled to her side, starting to doze off. Her mind picturing being curled up with Karkat on a bed.

":33 i love you," she whispered.


End file.
